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排序方式: 共有526条查询结果,搜索用时 15 毫秒
121.
Ken Hirota Yoshihiro Nakayama Masaki Kato Shingo Nakane Toshiyuki Nishimura 《International Journal of Applied Ceramic Technology》2009,6(5):607-616
Carbon nanofiber (CNF)-dispersed B4 C composites have been synthesized and consolidated directly from mixtures of elemental raw powders by pulsed electric current pressure sintering (1800°C/10 min/30 MPa). A 15 vol% CNF/B4 C composite with ∼99% of dense homogeneous microstructures (∼0.40 μm grains) revealed excellent mechanical properties at room temperature and high temperatures: a high bending strength (σb ) of ∼710 MPa, a Vickers hardness ( H v ) of ∼36 GPa, a fracture toughness ( K I C ) of ∼7.9 MPa m1/2 , and high-temperature σb of 590 MPa at 1600°C in N2 . Interfaces between the CNF and the B4 C matrix were investigated using high-resolution transmission electron microscopy, EDS, and electron energy-loss spectroscopy. 相似文献
122.
A series of analyses was carried out to elucidate treatment of welding imperfection for simulating elastic-plastic behaviors
of steel plates under compressive loads. A thermal elastic-plastic analysis based on infinitesimal deformation theory was
carried out on a single-pass butt-welding of thin steel plates to predict welding distortion and welding residual stress.
The obtained welding distortion and welding residual stress were introduced into an elastic-plastic large deformation analysis
as initial imperfection. However, it was elucidated that welding distortion and welding residual stress could not be reproduced
precisely due to unbalanced force caused by the difference between both analysis theories. Therefore, it should be confirmed
whether the introduced welding distortion and welding residual stress were reproduced with high accuracy. Consequently, if
welding distortion and welding residual stress cannot be reproduced, the treatment such as the convergence calculation method
applied in this study should be done for precise elucidation of the elastic-plastic behavior of plates under compressive loads. 相似文献
123.
Kazuki Nakamura Shingo Nakagawa Hiroshi Matsubara Daisuke Tatsui Kiyotaka Seki Shinichiro Haruyama Fumio Teraoka 《Electrical Engineering in Japan》2015,190(3):45-56
We developed a high‐speed telecommunication system for use on railways to improve customer service and the efficiency of operator's telecommunications between ground facilities and trains under operation. We built a mobile telecommunication system, capable of achieving a transfer rate of 1 Gbps in theory, by utilizing laser beam communications technology. We carried out a field test using trains in active service, and obtained results in which a transfer rate of approximately 700 Mbps in the TCP layer was achieved between the ground and a train running at a speed of approximately 130 km/h . 相似文献
124.
Power Consumption Smoothing for Water Distribution System Based on Water Supply Management and Demand Adjustment 下载免费PDF全文
Two power consumption smoothing methods for a water transmission and distribution system based on water supply management and demand adjustment are proposed and evaluated by simulations. One is a power smoothing method with the achievable power target calculation. The other is a power smoothing method with demand adjustment that can achieve flat demand by effectively using the storage capacity of receiving tanks of heavy consumers. Simulation tests show that the former method is effective in attaining flat power consumption during a time zone with high water demand and that the latter method can achieve almost flat power consumption throughout the day. 相似文献
125.
In order to evaluate universities from various aspects, we propose a method of utilizing data envelopment analysis (DEA).
The management of universities is complex, and it is necessary to find out their strengths and weaknesses so that they may
become a better educational institute. In this sense, DEA contributes to the evaluation since it can show the efficiency of
universities based on multiple viewpoints. However, when the number of universities evaluated is increased, the results of
an evaluation are similar. Therefore, it is difficult to understand the specific points of each university. We propose a method
for developing evaluations by adapting the decision-making unit (DMU) to certain viewpoints. The utility and effectiveness
of the proposed method are shown by numerical experiments. 相似文献
126.
Shingo Kurosu Hiroaki Matsumoto Akihiko Chiba 《Metallurgical and Materials Transactions A》2010,41(10):2613-2625
The isothermal phase transformation behavior in a biomedical Co-29Cr-6Mo alloy without carbon or nitrogen was investigated
during aging at temperatures between 973 K and 1273 K (700 °C and 1000 °C) for up to 90 ks. Transformation from the γ to the ε phase did not occur at 1273 K (1000 °C) as the γ phase was more stable than the ε phase, and the σ phase precipitated at the γ grain boundaries. At 1173 K (900 °C), a γ → ε
1 phase transformation occurred by massive precipitation. Prolonged annealing at 1173 K (900 °C) led to a lamellar structure
of ε
2 and σ phases at ε
1/ε
1 boundaries by a discontinuous/cellular reaction, expressed by the reaction equation ε
1 → ε
2 + σ. After decreasing the aging temperature to 973 K (700 °C), transformation from the γ to the ε phase occurred mainly by isothermal martensitic transformation, but a lathlike massive ε
1 phase and ε
2/σ lamellar colonies were also observed at the original γ-grain boundaries. It is likely that not adding carbon results in the promotion of the massive transformation and the precipitation
of the σ phase during isothermal aging in the Co-29Cr-6Mo alloy system, whose composition corresponds to the ASTM F75 standard for
metallic materials for surgical implantation. The resultant isothermal transformation behavior of the present alloy is described
on the basis of thermodynamic calculations using Thermo-Calc. 相似文献
127.
Daiki Nakahigashi Shingo Aoki Zhongqi Sheng Hiroshi Tsuji Xiao-Jun Shi 《Artificial Life and Robotics》2009,14(2):110-113
To improve the precision of memory-based reasoning (MBR) for ordinal data, this article presents correlation-based similarity metrics. The basic idea of this research is an intuitive assumption: if the correlation between the answer and one feature in a sample data set is large, the weight of this feature for predication should be large. To validate this proposal, we promote “leave-one-out cross-validation” for 53 examples which were collected from Japanese client companies who outsource software development to vendor companies. Three measures, including mean absolute error, variance of error, and precision, are compared among the proposed methods: the per-category feature importance (PCF), the per-feature category importance (PFC), the averaged category feature importance (ACF), and the cross-category feature importance (CCF). The Wilcoxon matched-pairs signed ranks test is also discussed. 相似文献
128.
Retsuo Kawakami Takeshi Inaoka Shingo Minamoto Yasuyuki Kikuhara 《Thin solid films》2008,516(11):3478-3481
GaN etching damage by capacitively-coupled RF Ar plasma exposure is significantly dependent on gas pressure and exposure time. At a low gas pressure (10 mTorr), the N/Ga ratio decreases by the physical etching effect with increasing exposure time, while the GaN surface morphology is smooth. At a high gas pressure (50 mTorr), there are other effects such as UV radiation, by which the GaN surface morphology becomes rough as the exposure time increases from ∼ 60 min. 相似文献
129.
Longitudinal microgrooves were assumed on the circular journal bearings and static and dynamic characteristics were investigated by solving the modified Reynolds equation for a rough bearing surface. It was found that the dynamic characteristics of the journal bearings were improved by longitudinal microgrooves or truncated micro-grooves on the bearing surface while the static characteristics, such as load-carrying capacity and friction coefficients, were not changed by the microgrooves. Calculations regarding the linear stability of a symmetrical rotor supported by two journal bearings were also carried out and it was found that the stable region was expanded on the stability chart by microgrooves. 相似文献
130.
A new simulation method was developed for analyzing the grinding mechanisms of aggregates in wet ball milling. The calculation of the following five behaviors is needed in this case: dynamics and breakage behaviors of aggregates, collisions of aggregates, a motion of fluid including aggregates, ball-fluid interaction forces and aggregate-fluid interaction forces. The dynamic and breakage behaviors of aggregates were calculated by advanced discrete element method (ADEM). The collisions of aggregates were represented by DEM. The motion of fluid including aggregates was solved by spatially-averaged equations of the fluid with finite difference method (FDM). The ball-fluid interaction forces were calculated by immersed boundary method (IBM). The model for the aggregate-fluid interaction forces has not been established, so that a new simulation model for estimating them was developed and named ADEM-computational fluid dynamics (ADEM-CFD) model. The ADEM-CFD model was verified by comparing the fluid drag coefficients obtained by White’s equation. The new simulation method considering the five behaviors was validated by comparing with an experiment about dynamic and breakage behaviors of aggregates around a falling ball in liquid. It is found that the new simulation method proposed could analyze the dynamic and breakage behaviors of aggregates in wet ball milling. 相似文献